I know you thought you were helping, but the soaks are what ruined his shed.
First of all, calm down. Take a deep breath, realize we all make mistakes in the beginning, and go from here.
Now that he's had his bad shed, you can soak him, or do what I like to and get a clean pillowcase, dampen the pillowcase, put the snake inside the damp pillowcase, tie the pillowcase shut. Put the pillowcase in a warm spot and leave him alone for 20 minutes or so. He'll rub most of the shed on his own.
He does not need to see a vet. The vet can't do anything for him you cannot do at home, and you'll save money. You don't need to use that shed aid either, it doesn't really help. I know, I used it for over a year before I discovered what a waste of money it is.
When you see him getting ready to shed again, just bump the humidity a little, and it doesn't need to be much, and he'll do the rest.
Gale